The value of humidifiers in millions of American homes and offices is well known for preventing dry skin and noses, as well as an aid to preventing contraction of certain respiratory diseases. However, there are probably twice as many automobiles, trucks, and other conveyances as there are homes. Yet, no humidity system to alleviate this dry condition has been offered for cars, trucks, and other mobile units. A person may ride in a dry oven-type heated compartment in winter months where the relative humidity is often 10 percent or less moisture than in the Sahara Desert. There are many truck drivers who spend eight hours, or so, in such an atmosphere during their daily working periods.
A typical experiment verifies this dry condition. A humidiquide indicator placed in a passenger car in the winter months when the outside temperature is between 20.degree. F. and 30.degree. F. may indicate a relative humidity of between 30 and 40 percent. The car is driven for fifty minutes with the car heater temperature set at 72.degree. F. The air circulating through the car heater now shows the relative humidity to be down to 10 to 15 percent.
Repeating the same experiment while adding moisture to the car by means of a hydrometeor, the humidiguide indicator may be kept at about 40 percent relative humidity.
The surprising thing, which has probably kept inventors from offering such a system, is that one would expect the windows to fog up, but they do not, due to the high volume of air curculating through the heater duct system and the allowable moisture at a given temperature. At a barometric pressure of 30 inches of mercury and a temperature of 72.degree. F., the weight of moisture necessary to produce 40 percent relative humidity is only 3.2 grains of moisture per cubic foot. In layman's terms, this is less than seven thousandths of an ounce.
All currently available inexpensive humidity indicating instruments have a certain lag response time; however, as one can imagine, as in the example given, if it takes 50 minutes of 72.degree. F. circulating air to reduce the indicating humidiguide to 10 percent relative humidity, the moisture replacement necessary to meet the aim of this invention is not a large quantity. A water dispensing container of one liter would probably meet most needs to provide a sufficient period of time before refilling.
The novel apparatus of the instant invention may be installed in a mobile vehicle in either one of three different ways. These three methods show how a controlled quantity of water vapor can be maintained to satisfy a set relative humidity in a vehicle, either by means of evaporation using one of several hot areas of the vehicle; use of a unit heater powered by battery wattage; or by a mechanical pressure release system using a D.C. motor. To meet these aims, a number of objectives are claimed as follows:
The principal objective of the present invention is to provide a controlled relative humidity system for mobile vehicles such as cars, trucks, buses, trains, and the like.
Another objective is to provide a suitable water vessel with integral controlled water and vapor valve inlets and outlets.
Another object of the invention is to provide a controlled moisture dispensing system that discharges vapor directly into the conventional heating duct of the vehicle.
Another objective is to provide a controlled flow of water from a main liquid container to a smaller vessel located in one of the hot zones of the vehicle for the purpose of converting water to steam or vapor.
Another objective is to provide a simplified modular system using a battery heater for converting the controlled flow of water to vapor.
Another objective is to include an electrical circuit and humidity control which holds the desired preset percentage of relative humidity in the driver and/or passenger compartments.
Another objective is to provide an electrical and humidity control circuit which functions only in the "on" position when related conditions of all associated elements are in the correct mode of influence.
Another objective is to provide a portable, completely self-contained, automatic moisture regulating and dispensing unit that can be plugged into the cigarette lighter receptacle of the vehicle.
Another objective of my invention is to provide an even more simplified self-contained, portable system for controlling relative humidity in a vehicle, that also gets its power from a plug-in arrangement using the cigarette lighter receptacle, and vaporizes moisture by a motor-driven pressure pump.
To sustain a relative humidity in the cab of a truck or car at between 30 and 40 percent is the objective of my invention to provide better health and comfort for winter driving. With this objective in mind, details of my humidifying system for mobile transportation units is hereby disclosed. Other objectives of the invention will become apparent as one studies the description of the preferred embodiments and the respective diagrammatic drawings.